Advances in fetal cardiac imaging.

During the past 25 years, two-dimensional imaging of the fetal heart has evolved into a sophisticated and widely practiced clinical tool, but most heart disease still goes undetected until sometime after birth, despite routine fetal ultrasound evaluations. Over the next 25 years, tremendous advances in fetal cardiac imaging, including three-dimensional imaging, promise to revolutionize both the prenatal detection and diagnosis of congenital heart disease. Image resolution continues to improve year after year, allowing earlier (10-15 week) visualization of the fetal heart, as well as the detection of subtle valvar abnormalities that may progress to serious forms of ventricular hypoplasia at term. However, fetal cardiac imaging remains constrained by limited sonographic windows. To improve the prenatal detection of congenital heart disease, outflow tracts are increasingly included along with the routine screening four-chamber view. However, while the four-chamber view resides within a single plane, lending itself to tomographic evaluation with two-dimensional ultrasound, the outflow tracts (and most forms of congenital heart disease) do not reside within a single plane. For these and other reasons, three-dimensional imaging of the fetal heart ultimately may improve the detection of outflow tract abnormalities, and facilitate comprehension of complex forms of congenital heart disease. Finally, other imaging modalities, including but not limited to Doppler tissue imaging and magnetic resonance imaging, continue to evolve and to complement two- and three-dimensional sonographic imaging of the fetal heart. As a result of these ongoing advances in the prenatal detection and assessment of congenital heart disease, these are exciting and glorious times for the field of fetal cardiac imaging.